Pallets for the storage and transportation of articles are in widespread usage. The most common example is a pallet which includes a solid platform with runners on the bottom to support the platform above some underlying surface or article, or a plurality of slats joined to the runners for the same purpose. The spacing between the slats and the underlying surface is defined by the thickness of the runners. In turn this thickness is determined by the situations in which the pallet is to be used. If it is a forklift pallet, then the thickness must be at least as great as the thickness of the forklift blades. Another consideration is to provide adequate columnar strength to support the loads transferred from the slats or platform. Still another deteminant, especially as to the slats is that there be sufficient bending strength to resists bending forces applied by the load which generate a tensile stress in the bottom of the slat.
It is a simple matter to over design a pallet. Reduced to absurdity, a heavy steel plate with thick-walled tubular steel runners could be expected to handle almost any load that would be manipulable by a forklift. This absurdity illustrates two important aspects of forklift design: cost and weight.
Pallets are subjected to rough usage, and their useful life before repair, especially wooden pallets, is surprisingly short. It is common to use wooden slats and runners that are nailed together to form the pallet. Wood is a relatively inexpensive material, and the cost of a assembling the pallet is acceptable. for many uses, especially for closed circuit shipping, where the pallet is returned for re-use, this is an acceptable construction. However, it is bulky, and it is heavy.
For one-way pallets the situation is often very different. These frequently are used for air freight shipments, and in other transactions which are weight-related as well as volume-related. When heavier pallets are used, it is not unusual for shipping capacity to "weigh out" before it "cubes out". This is to say that where the weight capacity is reached there still remains unfilled volume that cannot be utilized because the weight limit has been reached. The pallet weight therefore reduces the number of articles that could otherwise be shipped.
For example, an inexpensive wood pallet weighs about 60 pounds and presently costs about $4.85. In a routine shipment involving about 25 such pallets, weight savings attainable with the use of this invention (which weighs only about 61/2 pounds for many useful embodiments), enable the shipment to contain one more pallet full of articles.
The foregoing example relates weight and cubage. There is another even more pertinent example, where the pallets are used in air freight shipments in which weight is a primary determinant of shipping costs. At the present time, airfreight from California to Australia costs about $2.51 per pound, and this rate includes the pallets. The articles must usually be palletized, and the weight of the pallet is a severe economic burden.
It follows from the above that a more expensive pallet which weighs less can be the most economical device to use. Obviously all of the parameters must be taken into account, but it is a fact that there are literally thounsands of applications where a costlier pallet that will be discarded after one use will be on balance the most economical choice. If for some reason the pallet can be reused or used for another purpose, the economy is even greater.
Accordingly, it is not the objective of this invention to produce the lowest priced pallet. It is to produce a pallet adequate for the intended purposes with a lesser tare weight to justify the increased cost and still create net savings.
The term "adequate for the intended use" defines another objective- to provide just enough strength, of course with the least practicable cost and weight.
It is an object of this invention to provide such a pallet, utilizing a composite structure, and to the maximum extent to use commonly available materials such as are used in the building trades. Such materials themselves have long been subjected to intense scrutiny as to strength and economy of cost, and are ideally suited for use in structures such as pallets.